The utility model discloses a flexible explosion-proof sleeve for a cable intermediate joint. The flexible explosion-proof sleeve comprises an explosion-proof sleeve main body, wherein the explosion-proof sleeve main body is formed by wrapping a flexible sheet-shaped structure around a cable intermediate joint for a circle; two contacted edge parts of the explosion-proof sleeve main body are fixedthrough a locking piece after the explosion-proof sleeve main body is wrapped around the cable intermediate joint for one circle, and the two contacted edge parts of the explosion-proof sleeve main body are fixed through nylon screws and then are sealed through a sealant; pressure release valves are arranged at the two ends of the explosion-proof sleeve body, and the two ends of the explosion-proof sleeve body and the cable are sealed through sealing adhesive tape. The explosion-proof sleeve is small in size and can be installed in various cable channel environments, the application range ofthe cable explosion-proof sleeve is widened, and the coverage rate of the middle head explosion-proof device is increased; in addition, pressure release valves are installed on the two sides of the protective sleeve, and when the pressure in the connector reaches a threshold value, pressure can be released safely.